"A door is a device that allows ingress and egress by means of a revolute joint that is controlled by a handle that one can grasp with forceful actuation."

That may sound overly-complex, but this kind of description is important when telling something that isn't human how to navigate a complex environment like a house. Because HERB is a robot butler meant to deal with all kinds of different situations like this, he works on his own to figure out problems.

He's not that great at it yet, but he's getting better.

To open a door, HERB first needs to analyze what kind of door he's looking at and the environment he is in — how far away the door is and how he could interact with it to make it revolve open. Then, he figures out where the handle and hinges are on the door. He makes his move:

After analyzing the situation, HERB takes the plunge. But when he gets his hands in the door, he runs into a problem and gets stuck:

HERB doesn't have the advantages that we do of proprioception — the feedback we get when we pull on something. When we open a door, we can feel the weight of the door and the resistance to pulling straight. We know to start pulling the door to the right, toward the hinge, and not just straight at us, because of what we feel when we pull the door.

You'd get stuck too if you tried to open a door just by pulling it toward you. We've just opened so many doors over our lives that our bodies remember the motion required, without having to think about it.

So, admit it: You underestimated doors. Watch the full episode next week to learn how to open them.

HERB eventually gets out of the sticky situation with a pretty ingenious solution. Watch the entire clip, provided to us by National Geographic Channel, to see HERB in action. You won't regret it, especially if you want to hear a robot swear: